1. Field of the Invention
The invention is directed to purified and isolated polypeptides, the nucleic acids encoding the polypeptides, and processes for production of recombinant forms of the polypeptides. This invention is also directed to antibodies that specifically recognize the polypeptides, compositions containing the polypeptides, and to the use of these materials in various assays. In particular, the polypeptides, the nucleic acids encoding the polypeptides, and the antibodies are useful for the detection of human B cell lymphomas, enhancing the production of interferon xcex3 (IFN-xcex3), enhancing the growth of NK cells, treating viral infections and tumors, and enhancing the activity of cytotoxic T lymphocytes (CTLs).
2. Description of Related Art
1. Lymphomas
The malignant lymphomas represent multiple diseases with diverse morphologic and clinical expressions. Morphologic classification schemes have been shown to be useful in delineating natural history, prognosis, and response to therapy. However, in some instances, distinctive morphologic entities may be very closely related clinically or biologically or both, whereas other diseases that share morphologic similarities may be clinically and biologically quite distinct. Thus, immunological methods have become essential tools for the diagnosis and classification of certain human tumors, particularly for leukemias and lymphomas.
More particularly, some patients carrying malignancies have been found to produce antibodies against tumor-associated or other malignant cell-associated surface determinants as well as against a variety of differentiation and other non-tumor antigens. Several very sensitive immunological procedures have been developed for the detection of such antibodies.
A variety of other markers of hematopoietic malignancies allows clinically valuable categorizations, which are not possible by morphological or histochemical parameters. These markers can also be detected using immunological procedures. One of the main advantages of these procedures over other methods for the measurement of tumor-associated markers is their high level of sensitivity, with the ability often to detect a substance at nanogram or even picogram levels. In addition, immunological tests afford the ability to discriminate among substances with closely related structures and thereby to identify tumor-associated analogs found in normal, nonmalignant states.
Many tumor-associated markers have been detected in the sera or other body fluids of patients with malignancies. A few of these markers have been sufficiently restricted to tumor-bearing individuals to aid in detection or differential diagnosis (or both) of malignant disease. However, most markers have been found to lack sufficient specificity for such applications, with an appreciable frequency of elevated marker levels in patients with nonmalignant diseases (i.e., false positive results).
In addition, malignant lymphomas are usually an admixture of a neoplastic element and normal elements or both. A cell suspension prepared from a malignant lymphoma will consist of a mixture of benign and malignant cells, and the malignant cells may not necessarily be in the majority. To determine the phenotype of malignant cells, it is necessary to identify those markers associated with neoplastic cells.
It should be evident that there exists a need in the art for the identification of additional cell surface markers associated with malignant conditions. In particular, there is a continuing need for cell surface markers associated with malignant lymphomas. The identification of specific cell surface markers associated with malignant lymphomas will aid the detection of malignancies associated with these markers.
2. NK cells
One of the major types of circulating mononuclear cells is that of the natural killer, or NK, cell (M. Manoussaka et al., Journal of Immunology 158:112-119, 1997). NK cells are a cell type derived from bone marrow precursors (O. Haller et al., Journal of Experimental Medicine 145:1411-1420, 1977). NK cells appear to be closely related to T cells and the two cell types share many cell surface markers (M. Manoussaka et al., 1997). Although NK cells are cytotoxic cells as are some T cells; unlike T cells, NK cells do not express the T-cell receptor or CD3 components (P. Scott and G. Trinichieri, Current Opinion in Immunology 7:34-40, 1995; G. Trinichieri, Adv. Immunology 47:187-376, 1989). NK cells commonly express CD16 and CD56 antigens (K. Oshimi, International Journal of Hematology 63:279-290, 1996). Similar to cytotoxic T lymphocytes (CTL), NK cells are capable of exerting a cytotoxic effect by lysing a variety of cell types (G. Trinichieri, 1989). NK cells are capable of exerting cytotoxicity in a non-MHC restricted fashion (E. Ciccione et al., J. Exp. Med. 172:47, 1990; A. Moretta et al., J. Exp. Med. 172:1589, 1990; and E. Ciccione et al., J. Exp. Med. 175:709).
NK cells mediate some of their functions through the secretion of cytokines, such as interferon xcex3 (IFNxcex3), granulocyte-macrophage colony-stimulating factors (GM-CSFs), tumor necrosis factor xcex1 (TNF-xcex1), macrophage colony-stimulating factor (M-CSF), interleukin-3 (IL-3), and IL-8 (P. Scott and G. Trinichieri, 1995).
Cytokines including IL-2, IL-12, TNF-xcex1 and IL-1 can induce NK cells to produce cytokines (P. Scott and G. Trinichieri, 1995). IFNxcex3 and IL-2 are strong inducers of NK cell cytotoxic activity (G. Trinichieri et al., Journal of Experimental Medicine 160:1147-1169, 1984; G. Trinichieri and D. Santoli, Journal of Experimental Medicine 147:1314-1333, 1977). NK cells can be stimulated and expanded in the presence of IL-2 (K. Oshimi, International Journal of Hematology 63:279-290, 1996). IL-12 has been shown to induce cytokine production from T and NK cells, and augment NK cell-mediated cytotoxicity (M. Kobayashi et al., Journal of Experimental Medicine 170:827-846, 1989).
NK cells can lyse a variety of cell types, including normal stem cells, infected cells, and transformed cells (D. See et al., Scand. J. Immunol. 46:217-224, 1997). Cells that lack MHC class I are susceptible to NK cell-mediated lysis (H. Reyburn et al., Immunol. Rev. 155:119-125, 1997). The lysis of cells occurs through the action of cytoplasmic granules containing proteases, nucleases, and perforin (D. See et al., 1997). Antibodies directed against CD2 and CD11a inhibit the cytotoxic effect of NK cells (O. Ramos et al., J. Immunol. 142:4100-4104, 1989; C. Scott et al., J. Immunol. 142:4105-4112, 1989). NK cells can also lyse cells by antibody-dependent cellular cytotoxicity (D. See et al., 1997).
NK cells have been shown to destroy both extracellular protozoa and the cells infected by protozoa (T. Scharton-Kersten and A. Sher, Current Opinion in Immunology 9:44-51, 1997). In most instances, cytotoxic activity appears to be dependent upon lymphokine activation (T. Scharton-Kersten and A. Sher, 1997).
NK cells have been implicated as mediators of host defenses against infection in humans with varicella zoster, herpes simplex, cytomegalovirus, Epstein-Barr virus, hepatitis B, and hepatitis C viruses (D. See et al., 1997). Many viruses induce NK cell cytotoxicity, including herpesvirus and cytomegalovirus (C. Biron, Current Opinion in Immunology 9:24-34, 1997). The induction of NK cell activity is a result of the induction of IFN-xcex3 by viral infection, and NK cells are important in the early defense against many viral infections (C. Biron, 1997). The NK1+CD3- population of NK cells is the subset activated by viral infection (C. Biron, 1997). The response of NK cells to viral infection involves direct cytotoxicity and production of various cytokines such as IFN-xcex3 and TNF-xcex1 (C. Biron, 1997).
A number of human lymphoproliferative disorders of NK cells are known. These include NK cell-lineage granular lymphocyte proliferative disorder (NK-GLPD), NK cell lymphoma, and acute leukemia of NK cell lineage (K. Oshimi, International Journal of Hematology 63:279-290, 1996). Most patients with aggressive type NK-GLPD die of the disease (K. Oshimi, 1996). NK cell lymphoma is resistant to combination chemotherapy (K. Oshimi, 1996).
NK cells activated with IL-2 have been shown to have activity against human leukemia cells (L. Silla et al., Journal of Hematotherapy 4:269-279, 1995). Furthermore, NK cells appear to have a role in the treatment of chronic myeloid leukemia (K. Oshimi, 1996).
NK cells are involved in both the resistance to and control of cancer spread (T. Whiteside and R. Herberman, Current Opinion in Immunology 7:704-710, 1995). Furthermore, the presence and activation of NK cells may be outcome determinative; low or non-existent NK activity is associated with a high frequency of viral disease and cancer (T. Whiteside and R. Herberman, 1995).
In view of the important role that NK and T cells play in vivo, in host defenses, tumor cell surveillance, and autoimmune diseases, there exists a need in the art for polypeptides suitable for the in vivo and in vitro enhancement of NK and T cell activity.
3. Interferon xcex3
The production of IFNxcex3 is a function of T cells and NK cells, and IFN-xcex3 activates antiviral immune reactions (E. De Maeyer and J. De Maeyer-Guignard, in The Cytokine Handbook, A. W. Thompson (ed.), Academic Press, 1994, pp. 265-288). IFN-xcex3preferentially inhibits Th2 proliferation, but not Th1 proliferation (T. F. Gajewski and F. W. Fitch, J. Immunology 140:4245-4252, 1988). IFN-xcex3 also plays an important role in macrophage activation and promotes proliferation of activated B cells (De Maeyer and De Maeyer-Guignard). These, and other effects of IFN-xcex3, indicate that increased in vivo levels of IFNxcex3 production serve as a general immune modulator.
IFN-xcex3 has been used clinically in treating chronic granulomatous disease, atopic dermatitis, systemic achlerosis, lepratmatous leprosy, common warts, hepatitis B infection, myelogenous leukemia, and metastatic melanoma (J. Mordenti et al., in Therapeutic Proteins, A. H. C. Kung et al. (eds.), W.H. Freeman and Co., 1993, pp.187-199). In view of the important role that IFN-xcex3 plays, in vivo, in immune modulation, there exists a need in the art for polypeptides suitable for the enhancement of in vivo and in vitro IFN-xcex3levels.
4. Cytotoxic T Lymphocytes
CTLs are an important in vivo defense against viral, and bacterial, and cancerous diseases, in that they lyse target cells bearing foreign antigens (G. Berke, in Fundamental Immunology, W. E. Paul (ed.) Raven Press Ltd., 1989, pp. 735-764. In view of the important role that CTLs plays, in vivo, in the immune response to infections and tumor surveillance, there exists a need in the art for polypeptides suitable for the enhancement of in vivo and in vitro CTL activity.
The invention aids in fulfilling these various needs in the art by providing isolated ULBP nucleic acids and polypeptides encoded by these nucleic acids. Specifically, one embodiment of this invention provides cell surface glycoproteins associated with human B cell lymphomas. In a broad sense, this invention pertains to novel polypeptides referred to herein as ULBP polypeptides, which are found on the surface of human B cell lymphomas. The present invention is specifically directed to mammalian forms of ULBP polypeptides in isolated and purified forms. Particular embodiments of the invention are directed to isolated ULBP nucleic acid molecules comprising the DNA sequence of SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO:9 and isolated ULBP nucleic acid molecules encoding the amino acid sequence of SEQ ID NO:2, SEQ ID NO:4, or SEQ ID NO: 10, as well as nucleic acid molecules complementary to these sequences. Both single-stranded and double-stranded RNA and DNA nucleic acid molecules are encompassed by the invention, as well as nucleic acid molecules that hybridize to a denatured, double-stranded DNA comprising all or a portion of SEQ ID NO: 1, SEQ ID NO:3, and/or SEQ ID NO:9. Also encompassed are isolated nucleic acid molecules that are derived by in vitro mutagenesis of nucleic acid molecules comprising sequences of SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO:9, that are degenerate from nucleic acid molecules comprising sequences of SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO:9, and that are allelic variants of DNA of the invention. The invention also encompasses recombinant vectors that direct the expression of these nucleic acid molecules and host cells stably or transiently transformed or transfected with these vectors.
In addition, the invention encompasses methods of using the nucleic acids noted above to identify nucleic acids encoding proteins having ULBP activity; to identify human chromosome number 6; to map genes on human chromosome number 6; to identify genes associated with certain diseases, syndromes, or other human conditions associated with human chromosome number 6, and to study cell signal transduction and the ULBP system.
The invention also encompasses the use of sense or antisense oligonucleotides from the nucleic acid of SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO:9 to inhibit the expression of the polynucleotide encoded by the ULBP gene.
The invention also encompasses isolated polypeptides and fragments thereof encoded by these nucleic acid molecules including soluble polypeptide portions of SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO:9. The invention further encompasses methods for the production of these polypeptides, including culturing a host cell under conditions promoting expression and recovering the polypeptide from the culture medium. Especially, the expression of these polypeptides in bacteria, yeast, plant, insect, and animal cells is encompassed by the invention.
In general, the polypeptides of the invention can be used to study cellular processes such as immune regulation, cell proliferation, cell death, cell migration, cell-to-cell interaction, and inflammatory responses. In addition, these polypeptides can be used to identify proteins associated with ULBP ligands and ULBP receptors.
In yet another aspect, the invention includes assays utilizing these polypeptides to screen for potential inhibitors of activity associated with polypeptide counter-structure molecules, and methods of using these polypeptides as therapeutic agents for the treatment of diseases mediated by ULBP polypeptide counter-structure molecules. Further, methods of using these polypeptides in the design of inhibitors thereof are also an aspect of the invention.
Another aspect of this invention is the use of the ULBP nucleic acid sequences, predicted amino acid sequences of the polypeptide or fragments thereof, or a combination of the predicted amino acid sequences of the polypeptide and fragments thereof for use in searching an electronic database to aid in the identification of sample nucleic acids and/or proteins.
Isolated polyclonal or monoclonal antibodies that bind to these polypeptides are also encompassed by the invention, in addition to the use of these antibodies to aid in purifying the ULBP polypeptide. The antibodies, in turn, are useful for detecting the presence of ULBP polypeptides in human cell samples, which can be correlated with the existence of a malignant condition in a patient.
More generally, this invention provides methods of detecting B cell lymphomas using the polypeptides, DNA, and antibodies of the invention. The methods are based, for example, on immunological and DNA hybridization and amplification techniques.
Furthermore, this invention provides in vitro and in vivo methods of increasing IFN-xcex3 production, increasing NK cell proliferation and activation, and increasing CTL activity. In connection with NK cell activity, the ULBP polypeptides disclosed herein find utility as antiviral and antitumor therapeutics